Apparatus, and Corresponding Method, For Detecting the Anatomic Shape of a Subject

ABSTRACT

A light guide is provided. The light guide has an uneven light input face and even side faces, which are arranged directly downstream of the light input face. Furthermore, an optoelectronic component with such a light guide is provided.

FIELD OF APPLICATION

The present invention relates to an apparatus, and to a relative method, for detecting the anatomic shape of an object, and more in particular the anatomic shape of a living subject such as the human or animal body or, more in particular, a part thereof such as the end of a limb: a foot, a hand, or the trunk, the head, or similar organs.

More in particular, the apparatus according to the invention comprises a support structure, a chamber for housing the part whose anatomic shape is to be detected and optical means for detecting the surface of said part.

PRIOR ART

In the field the need is known to reproduce, in the digital format, the shape of a human foot or head for making clothes or clothes accessories, for example, in the specific case, footwear or motorbikes crash helmets, which are as much conform to the morphologic characteristics of the subject as possible.

The digitalization of physical objects, both inanimate and, instead, anatomic parts or entire living organisms, is currently performed substantially with two methods so called: method with contact and method without contact.

All the manual, or automatic, instruments which physically and systematically touch the whole external surface of the body to be detected by means of a sensor whose reading head is able to return its own position in the space with respect to a predetermined reference origin belong to the first category.

The result of such scanning is a group of coordinates of space points or however referred to orthogonal axes x-y-z.

Instead, all those systems which use, in place of a physical reading head, an optical, or of other nature, irradiation, which is reflected by the body and allows to reconstruct its surface geometry, belong to the second category.

In particular, known optical instruments are configured so as to move a radiation source which explores all the surface of the body, i.e. move the piece to be scanned, for obtaining a complete covering of the same. Afterwards, the surface geometry is reconstructed on the basis of the reflected radiation. The reconstruction occurs by means of triangulation calculations of the known type.

The range of instruments belonging to this category is very wide and the precision degree is variable according to a fundamental parameter: the dimension of the radiation pencil, or beam, which performs the function of reading head, when the radiation is reflected or read by the detectors.

Currently, some known optical instruments use a laser radiation which allows to obtain a precise scanning of the subject surface.

In substance, the laser light, exactly thanks to the fact of being very coherent light, and that it keeps, in part, the coherence also as reflected beam, allows a very accurate triangulation of the reflection point, to the purpose of getting therefrom the space coordinates being closest to the real ones.

To such purpose, the known optical instruments are provided with calculation electronic units able to perform the triangulation calculation. It goes without saying, however, that the precision depends on and is function of variable factors linked to the body nature (color, surface finishing degree, reflection index), as well as of the specific goodness of the calculation unit.

All these known systems, although having attained in time a fairly good precision degree, have however a known and common drawback.

For attaining the desired precision degree, the body, or part thereof, is required to keep still for a relatively long time (from some tens of seconds to some tens of minutes, even some hours) or, vice versa, it is necessary to move it in a coordinated way, for allowing the radiation pencil to cover the whole surface; this is an evident obstacle when the subject is the anatomic part of a living subject or animal.

In order to overcome said limit, it has been suggested making a coating element of elastic material, such as for example a sock in case of the foot shape detection, adhere on the part, or subject to be detected.

The coating element is marked with a plurality of marking signs, i.e. graphic signs, which are printed on a neutral background of the coating element, and which can be optically detected by means of chromatic contrast with the background itself.

In order to obtain the desired digitalization, the part or subject to be detected is inserted into the chamber of an apparatus, such as the one described in U.S. Pat. No. 5,911,126, which comprises a plurality of image acquisition devices, distributed in the chamber, in order to acquire, from different points of view, a plurality of substantially simultaneous images, or in a rapid time sequence, of the foot and of the marking signs associated with the foot, so as to overcome the drawback due to possible movements made by the living subject during the detection of its shape.

A processing and calculation unit is connected to the image acquisition devices in an attempt to link the acquired images to each other and to calculate the spatial position of the marking signs present in the acquired images, obtaining the spatial points of the foot.

The solution known in the art, even if advantageous from many points of view, has drawbacks which have not yet been solved.

The main drawback lies in the fact that automatic recognition of the marking signs is substantially impracticable.

In fact, it has been noted that the calculation processing unit, even if used together with image detection devices with high resolution and sensitivity, is not able to reconstruct the shape of the part or subject with high definition and, therefore, reconstruct a credible morphology of the part or subject.

In particular, when the coating element is put on the part to be detected, the processing unit is no longer able to recognize and discriminate the plurality of marking signs as such. In substance, the processing unit, even if precise and powerful, cannot recognize the marking signs as such in the different images. In other words, the detection unit confuses the marking signs with each other, or with respect to the background fabric of the coating element and, therefore, an expert operator has to intervene to obtain a coherent result.

The technical problem underlying the present invention is therefore that of producing an apparatus overcoming the drawbacks of the previously described known apparatuses and making it possible to detect a surface morphology of an anatomic part of a living subject rapidly, automatically and with a high definition.

SUMMARY OF THE INVENTION

The solution idea underlying the present invention is that of unequivocally marking each of the marking signs by means of two discriminating, different factors independent from one another, namely the color and outline of the marking sign. In fact, it is the combination of these two discriminating factors, which ensures unequivocal recognition of each marking sign in the acquired images.

On the basis of such solution idea the technical problem is solved by an apparatus for the detection of an anatomic shape for a body, an object or a part of a living subject, for example the end of a limb, the apparatus comprising according to the invention:

-   -   a support structure defining a chamber for housing the part, or         subject, to be detected;     -   a coating element able to adhere onto the part or subject to be         detected, and     -   a plurality of image acquisition devices distributed in said         chamber for acquiring, from different points of view, a         plurality of substantially simultaneous, or in rapid time         sequence, images of said part, or subject.

According to the invention, the apparatus comprises multiple marking signs with different outlines and colors where the multiple marking signs are associated with the coating element and distributed so that each marking sign having a determined outline and a determined color is arranged adjacent to at least another marking sign having a different outline and/or different color.

The apparatus further comprises a processing unit connected to the image acquisition devices able to correlate the acquired images with each other and recognize each of the marking signs which appear in different images, by means of discrimination of the respective outline and the respective color, and a calculation unit to calculate the spatial position of each marking sign obtaining the spatial points of the subject, or the anatomic part, to be detected.

The above technical problem is also solved by a method for the detection of the shape of a living subject, or of a part thereof, according to claim 18.

Further characteristics and advantages of the apparatus and of the method according to the invention will be apparent from the following description of an embodiment thereof given by way of indicative and non limiting example with reference to the annexed drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic front view, partially sectioned, of the apparatus according to the present invention.

FIG. 2 is a top schematic view, partially sectioned, of the apparatus according to the invention.

FIG. 3 is a top view of a sock provided with codified marking points according to the invention, and worn adhering to a foot to be detected.

FIG. 4 is a bottom view of the sock in FIG. 3.

FIG. 5 is a bottom view of the sock in FIG. 3, under a condition where the sock is not worn on a foot.

FIG. 6 is a view of the sock in FIG. 3 divided into parts.

FIG. 7 is a view of a cloud of points obtained through computerized reconstruction means in CAD environment starting from the points, obtained without intervention, of the operator by the method according to the invention.

FIG. 8 shows a view of the reconstructed shape of a foot by connecting the points of FIG. 7.

DETAILED DESCRIPTION

With reference to the annexed figures, reference number 10 generally indicates an apparatus according to the present invention for the detection of the anatomic shape of a living subject such as the human or animal body or, more in particular, a part thereof such as the end of a limb: a foot, a hand, the head, the back, or similar organs.

Without being a limitation of the Applicant's rights, as shown by way of indicative and non limiting example, the apparatus 10 is used for the detection of the shape of a foot 11.

The following description is made with reference to the detection of the anatomic shape of the foot 11 for convenience of explanation only, it being understood that the apparatus 10 can be used for the detection of the anatomic shape of any other part of the human or animal body, such as for example: the head, the hand, the trunk, . . .

The apparatus 10 according to the present invention comprises a support structure 13 wherein a chamber 15 for housing the foot 11 is defined.

The structure 13 is formed, in the case of the shown solution, by a pair of elements 13 a and 13 b having elliptical shape being opposite arranged and crossed with respect to each other and each of them being mounted on two horizontal pins 14 a and 14 b.

In the case of the shown solution, the support structure 13 is completed by a casing 25, or counter-wall, having substantially ovoidal shape, which is contained in the inner space of the support elliptical elements 13 a and 13 b. The chamber 15 housing the foot 11 is formed inside the casing 25.

The casing 25 also has a side opening for inserting the foot 11 not shown in the drawings.

It goes without saying that the shape and the dimensions of the casing 25 and of the structure 13 are correlated to the dimensions of the subject to be detected, and they are thus not to be considered as limiting within the present invention.

The apparatus 10 also comprises a plurality of image acquisition devices, such as for example digital cameras 20, distributed around the chamber 15 housing the foot 11 for acquiring, from different points of view, a plurality of images of the foot 11.

Preferably, the cameras 20 are at least twenty and they are distributed around the camera 15 for carrying out a simultaneous shot of a plurality of overlapped images of the foot 11 from each point of view so as to cover the whole foot 11.

Thus more images of the foot 11, different from each other, are obtained. The cameras 20 are preferably synchronized for taking photographs simultaneously. According to an embodiment the images can be taken in close sequence, one after the other.

For convenience of illustration, it is to be noted that in FIGS. 1 and 2, the cameras 20, and the relative support elliptical element 13 a, which are close-up shot in the figures, are marked with a darker stroke, whereas the other cameras 20, and the relative support elliptical element 13 b, which are mid-shot, are marked with a lighter stroke.

Before being photographed by the cameras 20 for the acquisition of the plurality of images, the foot 11 is coated with an adhering coating element, such as for example a sock 36, or a sheath.

Preferably the sock 36 is made of thin, soft, elastic material, to adhere to the foot without altering its external appearance.

In the given embodiment, the sock 36 is in Lycra.

The sock 36 is provided with multiple marking signs 26 a, 26 b, 26 c, 26 d, 26 e, 26 f, i.e. graphic signs with such chromatic characteristics as to be acquired and clearly distinguished, in the images of the foot itself, from the neutral background fabric of the sock.

According to the invention, the marking signs 26 a, 26 b, 26 c, 26 d, 26 e, 26 f associated with the sock 36 are varied and variegated, in other words they have multiple colors and multiple different contours and outlines.

The term contour or outline is intended to mean in general that the marking signs 26 a, 26 b, 26 c, 26 d, 26 e, 26 f have multiple and different geometric forms or, with the same geometric form, they have different dimensions so that, thanks to said differences, they can be unequivocally distinguished.

In substance, each marking sign 26 a, 26 b, 26 c, 26 d, 26 e, 26 f is characterized by a predetermined geometric shape or size and by a predetermined color. The color and the outline are two discriminating factors whose combination unequivocally characterizes each marking sign 26 a, 26 b, 26 c, 26 d, 26 e, and 26 f.

To be recognized, it is important that the marking signs 26 a, 26 b, 26 c, 26 d, 26 e, 26 f are suitably distributed on the coating element 36 on the basis of the two above-described discriminating factors.

In fact, according to the invention, each marking sign 26 a, 26 b, 26 c, 26 d, 26 e, 26 f with a particular outline and a particular color, is arranged adjacent to at least a marking sign with a different outline and/or color.

For example, in the solution illustrated in FIG. 3, marking signs have been chosen, shaped like spots, having different outlines and colored with six different colors.

The colors are recognizable in FIGS. 3-5 on the basis of a different shade of gray: for example, reference number 26 a indicates green marking signs, reference number 26 b pink ones, reference number 26 c blue ones, reference number 26 d red ones, reference number 26 e violet ones and reference number 26 f yellow ones.

It should be noted that the limited number of colors chosen, in this specific case six (green, pink, blue, red, violet and yellow), favors discrimination of the marking signs 26 a, 26 b, 26 c, 26 d, 26 e, 26 f, since only colors with evident reciprocal chromatic contrast are used.

The marking points or signs 26 a, 26 b, 26 c, 26 d, 26 e, 26 f thus distributed are shot in the images by the cameras 20 and subsequently digitalized by means of computerized means so as to reconstruct the shape of the foot in three-dimensional format.

To such purpose, the apparatus 10 comprises a processing unit, schematically indicated in FIG. 1 with reference number 28, which is connected to the image acquisition devices 20 and is suitable to correlate the acquired images with each other and to recognize, by discriminating the color and the outline, each marking sign 26 a, 26 b, 26 c, 26 d, 26 e, 26 f which appear in more images simultaneously.

Recognition takes place on the basis of the unambiguous combination of color and outline associated to each marking sign 26 a, 26 b, 26 c, 26 d, 26 e, 26 f and on the basis of the recognition of at least one other marking sign 26 a, 26 b, 26 c, 26 d, 26 e, 26 f which is adjacent to it and which, as mentioned above, is characterized by different colors and/or outlines.

In substance, thanks to the predetermined combination of colors and outlines of each marking sign 26 a, 26 b, 26 c, 26 d, 26 e, 26 f and the comparison with the marking signs 26 a, 26 b, 26 c, 26 d, 26 e, 26 f which are adjacent to it, the processing unit 28 can automatically identify, without confusion, the marking sign 26 a, 26 b, 26 c, 26 d, 26 e, 26 f in different images and perform a triangulation calculation of the same point on several images acquired, in such a way as to obtain an overall image of the entire foot 11 in real time.

Preferably, in order to obtain an even more precise and exact recognition, the marking signs 26 a, 26 b, 26 c, 26 d, 26 e, 26 f are distributed on the coating element 36 in such a way that each marking sign 26 a, 26 b, 26 c, 26 d, 26 e, 26 f is surrounded by two or more marking signs 26 a, 26 b, 26 c, 26 d, 26 e, 26 f with a different outline and/or color.

For example, with reference to FIG. 3, it is possible to distinguish the marking signs with different outlines and colors, where each marking sign is surrounded by four marking signals with a different outline and/or color.

Preferably, as can be seen in the solution illustrated, the marking signs 26 a, 26 b, 26 c, 26 d, 26 e, 26 f with the same color are arranged in sequence according to predefined curved guide lines, some of which are given as an example with a broken line and indicated with the reference S in FIGS. 3 and 5.

Advantageously, moreover, the marking signs 26 a, 26 b, 26 c, 26 d, 26 e, 26 f with the same color and arranged along each curved guide line are of a similar size to each other, compared to those of another guide line.

The arrangement along guide lines S is preferable compared to a random arrangement for the fact that said guide lines S are correlated to the morphology of the anatomic part to be reconstructed. For example, in the case of the sock, the guide lines S are the guide lines of the shape of the foot.

Consequently, during the 3D geometrical reconstruction, the presence of the guide lines makes it possible to capture the required morphological characteristics with correct positioning on the anatomic part, avoiding an abundance/scarcity of information typical of random digitalization.

Moreover, it should also be noted that the arrangement on the same guide lines S of the marking signs 26 a, 26 b, 26 c, 26 d, 26 e, 26 f having the same color, represents a further distinguishing factor during recognition of the marking signs 26 a, 26 b, 26 c, 26 d, 26 e, 26 f. In fact, during recognition of the marking signs, the processing unit 28 can verify which marking signs 26 a, 26 b, 26 c, 26 d, 26 e, 26 f belong to a particular guide line S by their color.

The apparatus 10 also comprises a calculation unit 29 which calculates the space position of each individuated marking sign 26 a, 26 b, 26 c, 26 d, 26 e, 26 f, for getting, in real time, the space position of the corresponding points of the object of the anatomic part to be detected.

Preferably, the calculation unit 29 performs, for each homologous marking point 26 a, 26 b, 26 c, 26 d, 26 e, 26 f present in the single images, a triangulation calculation normally used in the photogrammetric technique for the reconstruction of surface morphologies.

In practice, thanks to the plurality of substantially simultaneous images of the foot 11 and to the recognition of the homologous marking points 26 a, 26 b, 26 c, 26 d, 26 e, 26 f in the different images, by means of triangulation calculations, the space position of the previously marked, homologous marking points 26 a, 26 b, 26 c, 26 d, 26 e, 26 f of the foot 11 is obtained.

According to an embodiment of the invention, for performing the correlation and the calculation of the position of the homologous marking points 26 a, 26 b, 26 c, 26 d, 26 e, 26 f an analysis and photogrammetric reconstruction algorithm of the images is used.

Thus, a file of space coordinates is obtained, which can be analyzed in three-dimensional (3D) environment CAD with obtainment of a so called cloud 30 of points 31 corresponding to the homologous marking points 26 a, 26 b, 26 c, 26 d, 26 e, 26 f (FIG. 7).

The surface of the foot shape is then reconstructed in the digital format by simply using the points of the cloud 30 (FIG. 8).

From the surface of the reconstructed shape significant section curves are then taken in a known way.

A reconstruction is thus obtained of the foot 11 morphology from the simple individuation and calculation of the space position of the marking points 26 a, 26 b, 26 c, 26 d, 26 e, 26 f signed on the foot 11.

In the case of the foot 11 image acquisition, it is enough to associate, with the surface of the foot, a total number of points comprised between 600 and 1200, but nothing forbids that the number can be higher or lower.

Evidently a different number of points can be requested depending on the complexity of the part to be detected but a careful distribution of said points on the coating is obviously practical both for simplification of the calculations and accuracy of the final result.

For better understanding the invention, the sock 36 of FIG. 6 is divided into a plurality of parts A, B, C, D (indicated with dot lines in FIG. 6) partially overlapped one on the other which ideally correspond to four images of the coating element acquired by as many cameras 20.

It is possible to observe that, thanks to the presence of the two discriminating factors, color and outline, of the marking sign 26 a, 26 b, 26 c, 26 d, 26 e, 26 f and to the previously chosen distribution of the same above mentioned marking signs, it is possible to compare and easily align the images A, B, C, D and thus automatically recognize the homologous marking points 26 a, 26 b, 26 c, 26 d, 26 e, 26 f present in the four images, also when the sock is put on the foot.

A triangulation calculation is subsequently carried out for the homologous marking signs 26 a, 26 b, 26 c, 26 d, 26 e, and 26 f.

Preferably in the illustrated solution, the apparatus 10 according to the invention allows to detect the shape of a foot 11 with a precision, i.e. with a number of points 31 per surface unit, locally differentiated.

To such purpose, the marking signs 26 a, 26 b, 26 c, 26 d, 26 e, 26 f are distributed with different concentration, or density, on the foot 11 surface according to the anatomic area of the foot 11 associated therewith.

example, in the case where it is necessary to detect the morphology of a portion of the foot 11, e.g. the heel T, due to the presence of a malformation or anomaly, the marking points 26 a, 26 b, 26 c, 26 d, 26 e, 26 f are arranged on said portion with a greater concentration, and colored with contrasting colors so as to identify said significant anatomic areas more precisely.

this way, a sock 36 is obtained provided with a greater number of marking points 26 a, 26 b, 26 c, 26 d, 26 e, 26 f on the heel T compared to another area of the sock 36, as illustrated in FIG. 5.

According to a preferred embodiment, the coating element 36 is marked with additional marking signs not illustrated in the drawings, which are arranged on the neutral background of the coating element 36 among the marking signs 26 a, 26 b, 26 c, 26 d, 26 e, 26 f.

Unlike the marking signs 26 a, 26 b, 26 c, 26 d, 26 e, 26 f, the additional marking signs are not used for the correlation of the above-mentioned images A, B, C, D, but serve to increase the number of points to be associated with a predetermined part of the subject to be detected.

In particular, when the images taken by different cameras 20 are correlated and aligned by means of the marking signs 26 a, 26 b, 26 c, 26 d, 26 e, 26 f, the additional marking signs are recognized and their position is defined by the processing unit 28. The so-recognized additional marking signs define a further number of points 31, in addition to those of the marking signs 26 a, 26 b, 26 c, 26 d, 26 e, 26 f, of the shape to be reconstructed, making it possible to obtain even greater definition of the foot morphology.

Preferably, the additional marking signs are smaller than the marking signs 26 a, 26 b, 26 c, 26 d, 26 e, and 26 f.

According to a further embodiment, for obtaining a differentiated distribution of the marking points 26 a, 26 b, 26 c, 26 d, 26 e, 26 f, the sock 36 is made in elastic material having locally differentiated elasticity according to the anatomic area intended to be coated. For example in the area of the heel corresponding to the above malformation or anomaly, the sock 36 has a lower elasticity with respect to the rest of the surface so as to ensure a lower local stretching of the fabric and thus a greater concentration/density of marking points 26 a, 26 b, 26 c, 26 d, 26 e, 26 f in such area.

As above mentioned, the calculation of the position of the obtained marking points allows to reconstruct a cloud of digital points 31, and thus allows a reconstruction of the surface in environment CAD 3D.

Once the cloud of digital points has been obtained, it is possible to perform a comparison between the obtained shape of the foot 11 and the shapes for footwear contained in an archive of known shapes.

Once the known shape being more similar to the shape of the analyzed foot shape has been detected, it is possible to detect also the shoe being most suitable to the morphology of the foot 11.

For performing the comparison it is possible to use computerized means adopting a known calculation algorithm, such as that of automatic alignment by means of Bounding Box followed by Boolean operations on the two detected bodies and leaving in evidence only the differences.

It is to be noted that the obtained calculation of the position of the homologous marking points 26 a, 26 b, 26 c, 26 d, 26 e, 26 f does not allow to precisely establish the absolute position of the points. For this reason to make the most correct comparison as possible between the obtained cloud 30 of points 31 and a known shape, it is necessary to know the absolute value of the space positions of the digital points 31 and thus of the dimension of the obtained shape.

To such purpose the apparatus 10 is provided with a memory containing data relative to a reference element 38 having known dimensions and measured under the same conditions as those of the foot 11, so as to allow a dimensioning of the coordinates of the detected points and thus an evaluation of their absolute position.

As alternative, the reference element 38 can be also housed in the same chamber 15 next to the foot 11 for being shot in the images.

As reference element 38 a common ruler can be used having graduated scale. According to an embodiment, as reference element 38 a graduated scale is used being projected on the foot 11.

According to a further embodiment, the graduated scale is fixed on the inner side of the casing 25 facing the camera 15 so as to be in the field of view of the cameras 20 and to be shot thereby.

According to still a further embodiment, for having a dimensional reference, a rigid and inextensible stripe, having known length, is applied on the sock 36.

Moreover according to a further characteristic of the invention, the apparatus 10 is made so as to allow a uniform lightning and without shadows of the subject, so as to make an ideal shooting environment of the subject and an easy distinction of the colors of the marking signs 26 a, 26 b, 26 c, 26 d, 26 e, 26 f.

In particular, as above anticipated, the camera 15 is closed by the casing 25 which is made in opaque material. On the casing 25 a plurality of holes are made and in each of them a corresponding camera 20 is inserted. The holes are exclusively intended for the housing of the lens of the cameras 20, thus ensuring a lightning homogeneity.

The apparatus 10 described up to now is used in the following way.

In a first moment, the marked sock 36 is worn by a user and it is put on the foot 11. The foot 11 is inserted in the casing 25 and placed in the housing chamber 15. Preferably, the foot is maintained suspended in the chamber, without being loaded.

In a subsequent step the cameras 20 are activated so as to acquire the foot images. The acquisition time is completely negligible, normally in the order of less than a second.

Once the images are acquired, the homologous marking points 26 a, 26 b, 26 c, 26 d, 26 e, 26 f present in the different images are recognized by discriminating the color and the outline and the relative space coordinates are calculated.

The computerized means automatically process the obtained points, they reconstruct the surface morphology of the foot and they compare it with shapes known in the archive.

From the comparison, the shape is detected being most suitable to the conformation of the analyzed subject and on the basis of the suitable shape the desired garment is chosen, such as the shoe for the foot, a crash helmet, a glove and the like.

The main advantage of the present invention stays in the possibility of digitalizing with high definition and reduced possibility of mistake, the shape of a living subject or of a part thereof with high precision and, at the same time, in a simple and quick way.

In fact, thanks to the fact that recognition of the various images of the homologous marking signs takes place on the basis of the combination of the two above-described distinguishing factors, it is possible to overcome the limit in the unequivocal recognition of the marking signs present in the apparatus of the prior art.

In this way, it is possible to avoid the subsequent long and costly work on the acquired images to distinguish the visualized marking points which are useful for the reconstruction of the true surface.

Another implicit advantage in the synchronized, or in strict time sequence, acquisition of the images, is given by the fact that it is possible to further minimize a possible error in the image detection due to a sudden subject movement.

A further advantage of the present invention is that of choosing a priori through the color tone and the multiplicity of outlines of the marking signs, or spots, the number of points necessary to reconstruct the foot morphology in the digital format, as a function of the required reconstruction precision.

In other words, the greater or lower discrimination of the points obtained with colors having more or less contrasting tomes and the higher or smaller concentration of points offers the possibility of varying, according to the need, the precision with which such morphology is to be reconstructed.

As above mentioned, the number of points digitalized with the apparatus and the method according to the invention is of some orders of magnitude lower (typically between 500 and 1000) with respect to the known ones, and with the difference that is possible to choose a priori also the most significant anatomic points which must be detected with the desired precision.

In this way, once the significant anatomic points of the body have been detected, it is possible to increase the precision of the shape reconstruction only in those significant points without excessively affecting the calculations of the computerized means.

A further advantage of the present invention is that the apparatus allows an easy and quick use by a user, and it does not require skilled staff. In this respect, it is to be noted that the apparatus uses only a few instants from the insertion of the foot in the casing for acquiring the images and giving back the three-dimensional image of the foot structure.

In this regard, the use of a garment to be put on at the detection is particularly advantageous for marking the subject to be detected. In the described case, a user wears the sock for the strictly necessary time of the detection, without any strain.

A further advantage of the present invention is the neutral detection of the subject or part to be detected, without being loaded, which makes it easier to process the calculated points.

In fact, the position of the part or subject detected in the absence of load can be used as a starting position for a subsequent deformation parameterized with load, a deformation which can be applied with precision once the morphological type and structure of the part is known.

Obviously, a technician of the field, with the purpose of meeting contingent and specific needs will bring several changes and variations, all within the scope of protection of the invention as defined by the following claims. 

1. Light guide having an uneven light input face and even side faces, which are arranged directly downstream of the light input face.
 2. Light guide according to claim 1, in which the cross-sectional area of the light guide increases with the distance from the light input face.
 3. Light guide according to claim 2, in which the cross-sectional area of the light guide increases more in a first portion than in a second portion of the light guide.
 4. Light guide according to claim 3, in which the first portion is arranged directly downstream of the light input face.
 5. Light guide according to claim 3, in which the side faces of the light guide in the first portion each form an angle(φ₁) with the cross-sectional area of the light guide.
 6. Light guide according to claim 4, in which the side faces (5) of the second portion each form a second angles (φ₂) with the cross-sectional area of the light guide.
 7. Light guide according to claim 6, in which the first angles (φ₁) are greater than the second angles (φ₂).
 8. Light guide according to claim 6, in which the first angles (φ₁) are between 125° and 140°.
 9. Light guide according to claim 8, in which the second angles (φ₂) are between 95° and 135°.
 10. Light guide according to claim 3, in which the length of the first portion is at most 20% of the total length (L) of the light guide.
 11. Light guide according to claim 10, in which the length of the first portion is at most 10% of the total length (L) of the light guide.
 12. Light guide according to claim 1, in which the light input face is concavely formed.
 13. Light guide according to claim 1, in which the light input face has one of the following curvatures: spherical, elliptical, aspherical, biconical, biconically aspherical or biconically spherical.
 14. Light guide according to claim 1, having a light output face, through which a large part of the electromagnetic radiation coupled into the light guide through the light input face leaves the light guide.
 15. Light guide according to claim 14, in which the light output face has a curvature.
 16. Light guide according to claim 15, in which the light output face has a convex curvature.
 17. Light guide according to claim 15, in which the light output face has one of the following curvatures: spherical, elliptical, aspherical, biconical, biconically aspherical or biconically spherical.
 18. Light guide according to claim 14, in which the light output face is formed by a free formed surface.
 19. Light guide according to claim 14, in which the light output face is even.
 20. Light guide according to claim 3, in which the side faces of the second portion are even.
 21. Light guide according to claim 3, in which the side faces of the second portion have a curvature.
 22. Light guide according to claim 21, in which the side faces of the second portion are formed, at least in places, in the manner of one of the following optical elements: CPC, CEC or CHC.
 23. Light guide according to claim 1, in which the light guide is formed as a solid body.
 24. Light guide according to claim 23, in which the light guide contains a transparent material.
 25. Light guide according to claim 24, in which the material has a refractive index of greater than
 1. 26. Light guide according to claim 25, in which the material has a refractive index of greater than 1.3.
 27. Light guide according to claim 23, in which the material comprises at least one of the following materials: PMMA, polycarbonate, PMMI or COC.
 28. Light guide according to claim 1, wherein the light guide is configured to reduce the divergence of a bundle of rays that passes through the light guide.
 29. Optoelectronic component, having a radiation source and a light guide with an uneven light input face, a large part of the electromagnetic radiation emitted by the radiation source being refracted as it enters the light guide.
 30. Optoelectronic component according to claim 29, in which the light input face is concavely formed.
 31. Optoelectronic component according to claim 29, in which the light input face has one of the following curvatures: spherical, elliptical, aspherical, biconical, biconically aspherical or biconically spherical,
 32. Optoelectronic component according to claim 29, in which the light input face completely encloses the radiation source.
 33. Optoelectronic component according to claim 29, in which the radiation source is given by one of the following optoelectronic components: light-emitting diode, light-emitting diode chip, VCSEL 